With so many electrical accessories available on the market these days, it is important to protect the investment of your time when passing wires through the firewall (or anywhere else) when creating your accessory looms.
Including a firewall boot might be a pain at first, but it makes a clean and professional looking install, while ensuring that your wires do not get chafed by the metal they are passing through, and the elements stay where they are supposed to—outside.
Daystar came up with this universal size rubber boot, that is made in the U.S. and reasonably priced around $13. Made from heavy-duty vulcanized rubber, just like your OEM boots, a 1 ¼-inch hole is all that’s required to get it seated. From there, the diameter can be adjusted by clipping the end of the boot, from 3/8-inch all the way up to 1-inch diameter looms. Complete the installation by securing your loom to the boot with a simple zip tie and be on your way.
You just went from zero, to hero with a professional level wire installation.